/Engine/Source/Developer/CollectionManager/Public/ICollectionManager.h
Gets the optional color for the specified collection
true if the collection was found, and the color was optionally filled in. If false, GetLastError will return a human readable string description of the error.
bool GetCollectionColor ( [FName](API\Runtime\Core\UObject\FName) CollectionName, [ECollectionShareType::Type](API\Developer\CollectionManager\ECollectionShareType\Type) ShareType, [TOptional](API\Runtime\Core\IO\TOptional)< [FLinearColor](API\Runtime\Core\Math\FLinearColor) > & OutColor ) const